Apparatus for distilling oils



Feb. 21, 1933. H. 1.. DOHERTY 1,898,246

APPARATUS FOR DISTILLING OILS Original Filed Feb. 4, 1920 5 Sheets-Sheetl Feb. 21, 1933. H, DOHERTY 1,898,246

APPARATUS FOR DISTILLING OILS Original F e Fe 4. 1920 5 Sheets-Sheet 2 mafter/nu: Wlgwenior Feb. 21, 1933. H. L, DOHERTY 1,393,245

APPARATUS FOR DISTILLING OILS Original Filed Feb. 4. 1920 5 Sheets-Sheet4 v fez IT! 1 1 1 I 1 w v 1111 I -FUMHHHHHMHHUH i 1 Feb. 21, 1933. H. L.DOHERTY APPARATUS FOR DISTILLING OILS Original Filed Feb. 4, 1920 5Sheets-Sheet 5 ue fo'e Patented Feb. 21, 1933 UNITED STATES PATENT?OFFICE HENRY L. DOHERTY, OF NEW YORK, N. Y., ASSIGNOR, BY MESNEASSIGNMENTS, TO HEAT TREATING COMPANY, OF NEW YORK, N. Y., A CORPORATIONOF DELAWARE APPARATUS FOR DISTILLING OILS Original application filedFebruary 4, 1920, Serial No. 356,263. Divided and this application filedJuly 7, 1920. Serial No. 394,489.

This invention relates to an apparatus for refining liquids and moreparticularly to an apparatus for distilling petroleum or mixtures ofhydrocarbon oils to separate them into their several constituents or toobtain a desired product by the decomposition or cracking of ahydrocarbon oil.

Crude petroleum and the crude product of the destructive distillation ofheavy oils consist of mixtures, in varying proportions, of a series ofhydrocarbons ranging from light, volatile members to heavy, pitch likesubstances, which are solid or semi-solid at ordinary temperatures. Whenaliquid mixture of this type is distilled, the lighter members are firstvaporized and the mixture begins to boil at approximately the boilingpoint of the lightest members. As the distillation is continued and themixture becomes poorer in the lighter constituents, the temperature ofthe boiling liquid gradually rises and the vapors given off contain lessof the lighter and more of the heavier constituents until the heaviesthydrocarbons which it is practicable to distill are vaporized. The vaporgiven off at any temperature during distillation may have a definiteboiling point and composition, but the composition of the mixturechanges constantly as the tempera ture rises. A rough separation of theoriginal mixture into its constituents to produce kerosene, gasoline,naphtha and other products, may be obtained by continuously condensingthe vapors formed and separately collecting the condensates producedbetween definite boiling point limits. Since the change in the characterof the vapors is gradual, the products thus obtained not only do nothave a definite boiling point but the boiling point varies over acomparatively wide range. Any given fraction will, moreover, contain aconsiderable amount of constituents belonging to neighboring fractions.To obtain a commercial product of definite composition and boilingpoint, the various fractions must be redistilled to free them ofundesirable compounds, thereby entailing additional losses and requiringadditional quantities of heat and several distillations of the products.

A sharp separation of the lighter from the heavier hydrocarbons isparticularly desirable in the case of the products formed in thecracking of oils, since the heavy constituents are usually returned tothe still and again submitted to the cracking operation. The heating ofthe oil in the cracking operation tends to break down all of thehydrocarbons to lighter products and to break up the lighter members topermanent gas and carbon. The return of any of the lighter members tothe cracking still, therefore, tends to unnecessarily increase theproduction of permanent gases and to correspondingly de-' crease theyield of the desired products.

In distilling processes generally, and especially in oil crackingprocesses, a uniform heating and accurate control of the temperature ofthe liquid is desirable. If the temperature throughout any part of thedistilling apparatus is not uniform, the operation in the correspondingstep of the process will vary and will interfere with the normaloperation of the process. For instance, in cracking hydrocarbon oils,the character of the reaction and of the reaction products varies withchanges in the temperature at which the reaction is carried on, a hightemperature tending towards the formation of permanent gases. If,therefore, the transmission of heat to the oil be accompanied with theestablishment of a temperature gradient or vari ation in temperature inthe oil, or if the temperature of the oil be not closely controlled,

the conditions most favorable to the produc- 8 tion of the desiredproduct may not be obtained, and the yield or efficiency of the processwill accordingly be reduced through the formation of excessive amountsof gases and other undesirable products.

The object of the invention is, therefore, to provide an apparatus forrefining liquids by which the liquid to be treated may be separateddirectly into fractions having boiling points lying within narrow andsharply defined temperature limits.

Another object of the invention is to provide a distilling apparatus inwhich a mixture of oils may be continuously separated by a singletreatment directly into fractions of definite and substantially constantboiling point limits and substantially free of constituents havingboiling points outside the boiling point limits of the fractions.

5 A further object of the invention is to provide an apparatus by whichheavy hydrocarbon oils may be continuously decomposed into lighterhydrocarbons and the lighter hydrocarbons thus formed may be separateddirectly into fractions having sharply defined boiling point limits.

A further object of the invention is to provide an apparatus fordistilling liquids in which a uniform temperature may be maintainedthroughout any portion of the liquid being treated and by which thistemperature may be readily and accurately con trolled.

With these and other objects in view, the invention consists in theapparatus described in the following specification and defined in theclaims.

' The various features of the invention are shown in the accompanyingdrawings; in which:

' Fig. 1 is a side elevation of a still embodying the preferred form ofthe invention;

Fig. 2 is a front elevation of the still shown in Fig. 1;

Fig. 3 is a plan view of the still shown in Figs. 1 and 2;

Fig.4 is a detailed front elevation of fractionating elements of theapparatus shown in Fig. 1, parts being broken away toillustrate theinterior construction;

Fig. 5 is a side elevation, partly in section of the condensing elementsshown in Fig. 4;

Fig. 6 is a front elevation, partly in sect-ion of heat recoveryelements of the apparatus shown in Fig. 1;

Fig. 7 is a side elevation, partly in section, o-fthe heat recoveryelements in Fig. 6; and

Fig. 8 is a detailed view of a gas heating furnace forming part of theapparatus shown in Fig. 1.

Thepresent invention is'a division of my ending application, Serial No.356,263, filed labruary 4c, 1920, for a process of distilling In theprocess covered by the above mentioned application, the oil to betreated is passed downwardly through a series of fractionating chambersand is heated to progressively higher temperatures by means of a heatedgas passing through the chambers countercurrent' to the flow of the oil.The gas is passed through each chamber in a large number of streams ofbubbles thereby agitating the oil and efi ecting an intimate contactbetween every portion of gas and oil. In this manner the oil is heatedto a uniform temperature in each chamber and the temperature may beaccurately controlled by controlling the temperature and quantity of gassupplied. The oil is finally brought to a temperature at which it isbroken up or cracked into lighter constituents which are absorbed andremoved by the upwardly passing stream of gas. From the finer oilheater, the residue of oil which remains undecomposed, together with tarand carbon formed by decomposition of the oil, fiow through a series ofheat recovery chambers in which it is cooled to progressively lowertemperatures by means of cold gas passing countercurrent to the passageof the oil residue and is'finally brought to substantially atmospherictemperature.

The gas in passing through the heat recovery chambers abstracts heatfrom the oil residue and is heated to a progressively highertemperature. The heated gas is withdrawn from the hottest of the heatrecovery chambers and is heated directly by means of a gas flame orother heating means, to a temperature above that which the oil isdecomposed or cracked. From the gas heater the gas passes directly intocontact with the hottest body of oil to be treated and passessuccessively upwardly through each body of oil in the series offractionating chambers.

In passing countercurrent to the passage of the oil, the gas is firstbrought into a heat interchanging relation'with each body of oil beforecoming into direct contact therewith, in such a manner that anyhydrocarbons which are condensable at the temperature of the oil will becondensed and removed before passing into the body of oil. The gas isthen bubbled directly through the; bodies of oil. By this treatment thehydrocarbons in the oil vapors are separated into a number of sharplydefined fractions and any light hydrocarbons are effectively removedfrom the oil undergoing treatment before it reaches the cracking zone.From the uppermost of the bodies of oil, the gas is taken through awater cooled condenser to remove the last traces of condensable vaporsand is returned to the heat interchangers to be recirculated,

through the apparatus.

Referring to the accompanying drawings, the oil to be treated iswithdrawn from an oil supply cistern 10 through a pipe 12 and forced bymeans of a pump 14 (Figs. 2 and through a pipe 16 to the uppermost of aseries of fractionating chambers 18, 20, 22, 24c, 26, 28, 30, 32 and 34.The oil passes from one chamber into the next lower one through a seriesof overflow pipes 36, 38, 40, 42, 4A, 46, 48 and 50, the overflow pipesbeing so arranged that each chamber will be filled with oil to the levelof the inlet to the corresponding overflow pipe. From the lowermostchamber 34, the oil flows through an overflow pipe 52 (Fig. 2) to acracking chamber or still 5% in which it comes directly into contactwith gas composed of light or non-condensible hydrocarbons at thehighest temperature and is heated to, and maintained at,

a temperature at which the oil is cracked or decomposed. \Vith certaincharacters of oil and under some temperature and pressure conditions thecracking reaction may begin and a portion of the oils be cracked in thchambers 34, 32 and 30.

The hot tar and other residues produced by the cracking reaction flowfrom the cracking chamber or still 54 through an overflow pipe 56 to theuppermost of a series of heat recovery or heat-transforming chambers 58,60, 62, 64, 66 and 68 (Figs. 1 and 2) passing from one chamber to thenext lower through a series of overflow pipes 70, 7 2, 74, 7 6 and 78.From the lowermost chamber 68, the oil leaves the apparatus through anoverflow pipe and a trap 82 from which it may be discharged into thesump 10 or sent through a pipe 83 to storage. In passing downwardlythrough the heat transferring chambers 58 to 68, the oil is cooled toprogressively lower temperatures by means of cold gas which is forcedinto the lowermost chamber 68 and passes upwardly, countercurrent to theoil, from one chamber to the next through a series of pipes 84, 86, 88,and 92. The gas is heated by contact with the hot oil residues toprogressively hi her temperatures as it passes upwardly through the heattransferring chambers. The heated gas passes from the uppermost chamber58 through a pipe 94 into an upright liquid separating pipe 96 (Fig. 1)in which any entrained liquid is separated from the gas and removedthrough a draw-off Valve 98. The gas is thereupon heated in a furnace100 to a temperature sufficient to cause the cracking of oil in thecracking chamber 54.

In heating the gas in the furnace 100 the gas is passed back and forththrough a series of heating tubes extending through the furnace andconnected by series of manifolds positioned outside of the walls of thefurnace. The gas to be heated is conducted from the liquid separatingpipe 96 through a connecting pipe 102 to the uppermost of a series ofmanifolds 104 at one side of the furnace (Figs. 1, 2 and 3). Themanifolds 104 communicate, through a number of heating pipes 106extending through the furnace, with a series of similar manifolds 108 onthe opposite side of the furnace in such a manner as to cause the gas topass back and forth in succession through the manifolds 104, heatingpipes 106, and manifolds 108 to the lowermost of the manifolds 104. Thegas in its passage through the pipes 106 is heated by the flame from agas burner 109 to a temperature above that require to crack thehydrocarbon oils undergoing treatment and is then conducted through aconnecting pipe 110 directly to the cracking chamber 54.

In the cracking chamber 54 the gas brought into intimate contact withoil which has been heated in its passage through the condenser heaters18 to 34. From the cracking chamber the gas passes successively throughthe fractionating chambers 34 to 18, passing from one chamber to thenext by means of connecting pipes 112 (Figs. 2 and 4). The cracking ofthe oil may be continued and completed in the chambers 30, 32 and 34 asthese chambers are at about the same temperature as the cracking chamber54, and they may therefore be included in the cracking zone.

In passing upwardly through the fractionating' chambers, the gas impartsits heat to the downwardly passing oil and is cooled to progressivelylower temperatures. After passing through the uppermost fractionatingchamber 18, the is conducted through a vapor pipe 114 (Figs. 2 and 4) toa foam collecting chamber 116 in which any foam or entrained liquid maybe separated from the gas and. returned to the chamber 18 through areturn pipe 118. The gas is withdrawn from the foam chamber 116 througha vapor pipe 120 to a seri s of coils 122 and cooled by means of a sprayof water from a water distributing pipe 124. From the condenser coils122, the gas is withdrawn through a pipe 126 to a pressure blower 128and returned through pipes 130 and 132 to the lowermost heatinterchanger 68.

Any loss in the quantity of circulating gas, either by combination orunion with the products of distillation or through a leakage from theapparatus, is replaced by a. supply of additional gas from a supply pipe134 (Fig. 3). The gas in the pipe 134 is held under a pressure slightlyabove the pressure maintained in the cracking still by means of atwostage compressor 136. To this end, gas from an external source is ledinto a low pressure cylinder 138 of the compressor 136 through a pipe140 and forced through a pipe 142 to a cooler 144 which may be of themultitubular type. From the cooler 144 the gas is returned through a.pipe 146 to the second cylinder 148 of the compressor 136 and forcedthrough the pressure pipe 134 to a gas inlet pipe 132 leading to thelowermost heat interchanger 68.

The construction of the fractionating chambers 18 to 34 and crackingchamber 54 illustrated in detail in Figs. 4 and 5 of the drawings. Eachchamber comprises a cylinlrical outer shell 150 through which the gasinlet pipe 112 passes and an interior cylinder 152 into which the pipe112 leads. The end of the cylinder 152 adjacent the inlet pipe is closedand communication between the interior of the cylinder and the interiorof the shell 150 at the other end. of the cylinder is closed by means ofa flange 154 formed on the cylinder and extending to the wall of theshell. A second, closed cylinder 15 is positioned within the cylinder152 in such a manner as to form an annular passage therewith and isprovided with an opening I 158 at the end opposite the inlet pipe 112.

The gas entering the cylinder 152 through the pipe 112 is thereby causedto pass through the annular space between the cylinders 152 and 156 tothe opening 158, bringing every part of the vapor into intimate contactwith the walls of the cylinder 152 to obtain a rapid and efiectiveequalization of temperature between the condensing vapors on the insideof the cylinder 152 and the cooler body of oil within the shell 150.After passing through the annular space between the cylinders 152 and156, the gas enters the cylinder 156 through the opening 158 and isbubbled directly through the oil in the shell 150. The

gas is distributed throughout the oil in the shell 150 through a numberof short pipes or nozzles 160 extending from the cylinder 156 throughthe cylinder 152 to the bottom of the shell 150 and provided with anumber of distributing serrations or notches at their lower ends. Thegas, in bubbling upwardly through the body of liquid in the shell 150,causes a rapid circulation of the oil, continually bringing freshportions of oil into contact with the outer wall of the cylinder 152 andequalizing the temperature throughout the body of the oil. he contact ofthe gas with the oil also absorbs oil vapors and carries them to thenext higher chamber, and tends to still further heat the oil and coolthe gas before passing into the next higher condenser heater. .Theliquid condensate in the cylinder 152 is withdrawn through a drawofi'pipe 162. The temperature of the oil in the chamber may be observed bymeans of a thermometer inserted through a thermometer well 164.

The construction of the heat transferring chambers 58 to 68 isillustrated in Figs. 6 and 7 of the drawings, and is somewhat similar tothat of the fractionating chambers 18 to 34. Each heat transferringchamber comprises an outer cylindrical shell 166 which is partly filledwith oil residues and an inner cylinder 168 into which the gas entersthrough an inlet pipe 86 passing through the outer shell 166. From thecylinder 168 the gas passes into the body of oil in the shell 166through a number of short pipes 17 0 extending downwardly to the bottomof the shell 166 and provided with a numb-er of notches at their lowerends. The gas entering the oil residues from the pipes 170 comes intointimate contact with the body of oil in the shell 166 and is thoroughlyheated before passing out of the heat transferring chamber. Thetemperature of the oil in the heat transferring chamber may be observedby means. of thermometers inserted through thermometer wells 172.

The condensates removed from the fractionating chambers 18 to 34 throughthe draw-0E pipes 162 pass through traps 172 and through aseries ofwater cooled tubes returned to the apparatus when the apparatus is usedfor cracking hydrocarbon oils.

A very flexible and accurate control of the temperature conditionsthroughout the entire process may be obtained by the use of the aboveapparatus. This is particularly important in cracking oils, in whichcase the temperature at which the processv is carried on is a veryimportant, if not the controlling, factor in the formation of. anydesired procluct. In heating the oil in the cracking chamber, 54 forinstance, the heating gas is divided up into a number of small bubblesuniformly distributed throughout the oil in such a manner that thetransfer of heat from the gas to the surrounding oil is almostinstantaneous and inasmuch as the bubbles are uniformly distributedthroughout the oil, the heating is uniform throughout the entirechamber. The temperature may be very accurately and readily controlledregardless of the temperature of the gas by controlling the relativevolumes of the gas and oil, and may be raised by increasing the rate offlow of the heated gas, or quickly decreased by shutting down the rateof flow of the gas for any given rate of flow of oil through theapparatus.

In the fractionating chambers, the mixture of vapors and gas isseparated into a thin layer adjacent the walls of the tube 152 so thatevery portion of the gaseous mixture comes into proximity to the heattransferring wall. The wall of the tube 152 is maintained atsubstantially the temperature of the oil in its respective chamber bythe agitating action of the upwardly passing bubbles of gas whichcontinually bring fresh portions of oil adjacent the wall of the tube152 and prevent the accumulation of heated volumes of oil on the outsideof the tube. The action of the gas passing countercurrent to the flow ofoil in connection with the effective heat transfer obtained, sweeps anylighter hydrocarbons in the downwardly passing off upwardly through theapparatus and serves to prevent the entrance of any of the lighterhydrocarbons which may be suitable for blending in gasoline or othervaluable proclucts, from entering the cracking zone and being broken upinto permanent gases.

Inasmuch as all of the heat contained in said fractionating the oilleaving the cracking zone is recovered by the circulating gas andreturned to the heating steps, the apparatus is very econom1- cal in itsuse of the heat taken up in the gas heating pipes.

Having described the preferred form of the invention what is claimed asnew is:

1. A liquid refining apparatus having in combination, a series offractionating chambers arranged for gravity feed, a series ofheat-transferring chambers arranged for gravity feed below saidfractionating series, a connection for the flow of liquid between seriesand said heattra sferring series, means to introduce the liquid to betreated into the upper chamber of the fractionating series, and means tocirculate a fluid through the heat transferring chambers to absorb heatfrom the liquid as it advances through them, and means to circulate theheated fluid through the fractionating chambers countercurrent to theiiow of the liquid therethrough.

2. A liquid refining apparatus having in combination,-a series offractionating chambers arranged for gravity feed, a series ofheat-transferring chambers arranged for gravity feed below thefractionating series, a connection for the flow of fluid between thesaid fractionating series and said heat-transferring series, means tointroduce the liquid to be treated into the upper chamber of thefractionating series, means to circulate a fluid through the heattransferring chambers to absorb heat from the liquid as it advancesthrough them, means to circulate the heated fluid through thefractionating chambers counter-current to the flow of the liquidtherethrough, and means for separating co-ndensates from vapors inchambers of the fractionating series.

3. A liquid refining apparatus having in combination a series offractionating chambers arranged for gravity feed, means for introducingthe liquid to be treated into the upper chamber of the series, means forwithdrawing residual liquid from the last chamber of the series, meansfor introducing a heated fluid into the lowest chamber of thefractionating series and for circulating the heated fluid through thefractionating chambers countercurrent to the circulation of the liquidtherethrough to progressively heat the liquid, and means for separatingcbndensates from vapors in the chambers of the fractionating series.

4. A liquid refining apparatus having in combination, a series of liquidchambers arranged. for gravity feed, means to introduce the liquid to betreated into the upper chamber of the series, means to withdraw residualliquid from the last chamber of the series, means to circulate in aclosed cycle a gaseous heating medium through said chamberscountercurrent to the flow of the liquid, and means for condensing fromthe gas, vapors removed from the liquid, and separately removing thesame.

5. A liquid refining apparatus having in combination, a series offractionating chambers connected for gravity feed, a series ofheat-transferring chambers connected for gravity feed, aliquid-transferring connection between the said fractionating series andsaid heat-transferring series, means to introduce liquid into the firstchamber of the fractionating series, means to withdraw liquid residuumfrom the last chamber of the heattransferring series, means to circulatea gas through said chambers countercurrent to the liquid flow, and meansto add heat to the gas as it flows from the heat-transferring series tothe fractionating series.

6. A liquid refining apparatus having in combination, a series offractionating chambers connected for gravity feed, a series ofheat-transferring chambers connected for gravity feed, a connection forthe transfer of liquid between the said fractionating series and saidheat transferring series, means to introduce liquid into the firstchamber of the fractionating series, means to withdraw liquid from thelast chamber of the heat-transferring series, means to circulate gasthrough said chambers, and means to circulate said gas through a heateras it advances from the heat-transferring series to the fractionatingseries.

7 A liquid refining apparatus having in combination, a series ofconnected liquid fractionating chambers, a series of heattransferringchambers, a connection for the flow of liquid from said fractionatingseries to said heat-transferring series, means for introducing liquidinto the first chamber of the fractionating series, means forwithdrawing liquid residuum from the last chamber of the heattransferring series, and means for circulating a gaseous heat-carryingmedium through each of the chambers of the series countercurrent to theliquid flow.

8. A liquid refining apparatus having in combination, a series ofseparated li uid treating chambers arranged for gravity eed insuccession, liquid-transferring means between the chambers arranged tomaintain a body of liquid in each chamber, means for conducting a gasand vapor from each chamber to the next preceding chamber, means forpassing a gaseous heating medium in a closed cycle through the series ofchambers, said means comprising means for passing the heating mediumthrough the liquid in each chamber, and means in the chambers forseparately condensing vapors from vapors and liquids in said chambers.

9. A liquid refining apparatus having in combination, a series ofseparated liquid treating chambers arranged for gravity feed, liquidtransferring means between said cham- 'bers arranged to maintain a bodyof liquid in each'chamber, an elongated gas distributing tube mounted ineach of the chambers, nozzles in said tubes for distributing gas within5 the chambers, said nozzles resting on the bottoms of the chambers anda conduit for the flow of gas fromeach of said chambers to the tube inthe next preceding chamber.

10. A liquid refining apparatus having in O combination a series ofseparated liquid treating chambers arranged for gravity feed, liquidtransferring means between the chambers arranged to maintain a body ofliquid in each chamber, a vapor condensing tube mounted in each of thechambers, a gas distributing tube mounted in each of said condensingtubes, means in said distributing tubes for distributing gas within saidchambers, a gas passage between the condensing tube and the distributingtube in each chamber and a connection for conducting gas from eachchamber to the condensing tube of the next preceding chamber.

11. A liquid refining apparatus havmg 1n 5 combination,a series ofseparated chambers arranged for gravity feed in succession, an elongatedgas-distributing tube mounted 1n each of the chambers, means fordistributing gas from the tube through the liquid in the 0 chamber inwhich the tube is located including pipes having slotted ends resting onthe bottom of the chamber, a connection for gas between each chamber andthe tube of the .7 preceding chamber, and means for transferring liquidbetween succeedlng chambers arranged to seal gas in one chamber fortransfer into the tube of the preceding chamber.

' 12. A liquid refining apparatus havlng in combination,'a series ofseparated chambers 0 arranged for gravity feed in succession, avapor-condensing tube mounted in each of the chambers, agas-distributing tube mounted in each of said condensing tubes, meansfor transferring liquid between said chambers, a connection for gastransfer between the distributing tube is locate and means each of thechambers and the condensing tube of the preceding adjacent chamber,means for distributing gas from the distributing tube into the interiorof the chamber in which for withdrawing the condensate from saidcondensing tubes. 13. A liquid refining apparatus having in combinationa series of liquid fractionating 5 chambers, a series oi":heat-transferring chambers, liquid-transferring means between saidchambers, gas-transferring means between said chambers, means tointroduceliquid into the first chamber of the fractionating series,

69 means to withdraw liquid residuum from the last chamber of theheat-transferring series, a gas passage connected between said first andlast chambers, means to circulate gas in a closed path through saidchambers and passage, and means to add heat to said gas while it passesfrom the heat-transferring series to the fractionating series.

14. A liquid refining apparatus having in combination a series of liquidfractionating chambers, a series of heat-transferring chambers,liquid-transferring means between said chambers, gas-transferring meansbetween 7 said chambers, means to introduce liquid into the firstchamber of the fractionatlng series, 7

means to withdraw liquid'residuum from the last chamber of theheat-transferring series, a gas passage connected between said first andlast chambers, a vapor condenser in said passage, means to circulate gasin a closed path through said chambers and passage, and

said chambers, means to introduce liquid into the first chamber 01" thefractionating series, means to withdraw liquid residuum from the lastchamber of the heat-transferring series, a gas passage connected betweensaid first and last chambers, means to circulate gas through saidchambers and passage, means to add heat to said gas while it passes fromthe heat-transferring series to the fractionating series, and adistributor in each chamber for distributing gas throughout the body ofliquid in the chamber.

16. A liquid refining apparatus having in combination a series of liquidfractionating chambers, a series of heat-transferring chambers, liquidtransferring means between said chambers, gas-transferring means betweensaid chambers, means to introduce liquid into the first chamber of thefractionating series, means to Withdraw liquid residuum from the lastchamber of the heat-transferring series, a gas passage connected betweensaid first and last chambers, means to circulate gas in a closed paththrough said chambers and passage countercurrent to the flow of liquid,and

means to separate vapors from the gas and liquid circuits in thefractionating chambers.

17. A liquid refining apparatus having in combination, a series ofliquid treating chambers arranged for gravity feed, means to introduceliquid to be treated into the upper chamber of the series, means towithdraw liquid residuum from the last chamber of the series, a gaspassage connected between said u) er and last chambers means tocirculate gas ina closed path through said passage and chambers, andmeansfor separating from said gas, vapors removed from the liquid.

18. A liquid refining apparatus having in combination a series of liquidtreating chambers arranged for gravity feed, means. for

introducing liquid to be treated into the upper chamber of the series,means to withdraw liquid residuum from the last chamber of the series, agas passage connected between said upper and last chambers, means tocirculate gas in a closed path through said passage and chambers, andmeans mounted within some of said chambers for separating from said gas,vapors removed from the liquid by the gas.

19. A liquid refining apparatus having in combination a series of liquidtreating chambers arranged for gravity feed, means to introduce liquidto be treated into the upper chamber of the series, means forwithdrawing liquid residuum from the lastchamber of the series, a gaspassage connected be tween said upper and last chambers, means tocirculate gas in a closed path through said passage and chambers, andmeans mounted within said chambers and in said passage for separatingfrom the gas, vapors removed from the liquid by the gas.

20. A liquid refining apparatus having in combination a series ofseparated liquid treating chambers ant liquid transferring meansconnecting said chambers, said chambers comprising elongated cylindricaltubes, 21 cylindrical vapor-condensing tube mounted within each chamberand having a diameter adapted to provide a comparatively narrow spacebetween the inner walls of the chamber tube and the outer walls of thecondensing tube, a cylindrical gas distributing tube mounted within eachcondensing tube, nozzles on said distributing tubes extending into thelower portion of said chamber tubes and sealed from said condensingtubes, a conduit for the flow of gas from each condensing tube to thedistributing tube mounted therein arranged to prevent the entrance ofcondensate into said distributing tube and a conduit for the flow of gasfrom each chamber tube into the condensing tube mounted in the nextpreceding chamber.

21. A liquid refining apparatus having in combination a series of liquidtreating chambers arranged for gravity feed, means to introduce theliquid to be treated into the upper chamber of the series, means to withdraw residual liquid from the last chamber of th series, means tocirculate in a closed cycle a gaseous heating medium through saidchambers counter-current to the flow of liquid, means for separatingfrom the gas, vapors removed from the liquid, and a foam separatorconnected with said upper chamber for the treatment of said gas.

22. A liquid refining apparatus having in combination, a series ofseparated liquid treating chambers and liquid-transferring means betweensaid chambers, said chambers comprising elongated cylindrical tubes,elongated cylindrical gas-distributing tubes mounted within said chambertubes, and

a conduit for conducting gas from each chamber tube into thedistributing tube mounted in the next preceding chamber tube, saidconduit including a casing surrounding said distributing tube.

23. A liquid refining apparatus having in combination a series ofseparated liquid treating chambers and liquid-transferring means betweensaid chambers, said chambers comprising elongated cylindrical tubes,cylindrical vapor-condensing tubes mounted within said chamber tubes andhaving a diameter which will provide a comparatively narrow spacebetween the inner walls of the chamber tubes and the outer walls of thecondensing tubes, a passage for gas from the inside of each condensingtube into said space in each chamber arranged to prevent the flow ofliquid condensate from the condenser into said chamber tube, and aconduit for the flow of gas from each chamber tube to the condensingtube mounted in the next preceding chamber.

24. An apparatus for carrying out the process described, comprising aseries of containers, means for passing liquid into the first containerand thence progressively through the other containers, means forintimately and profoundly agitating the liquid in each container, aheater for the last container, and a vapor conduit from the lastcontainer passing through the remaining containers back to the first ofthe series, and means for removing condensates in various portions of:said vapor conduit.

25. A liquid petroleum cracking apparatus having in combination a seriesof separate tubular chambers closed for operation under pressure andconnected to permit feed by gravity from the upper to the lower chamber,means for conducting a heating gas through the chambers countercurrentto the flow of the liquid therethrough, a heat inter changing unitconnected with the lowermost chamber of the cracking chamber serieshaving connections for circulating the heating gas therethrough toextract heat from residual oil passing through the heat interchangerunit, a heater, connections for circulating the gas from the heatinterchanger unit through the heater and introducing it into the lowerchamber of the cracking chamber series, means for returning gases fromthe upper chamber of the cracking series to the heat interchanger unitand means for separating a vapor fraction from the vapors pass ingthrough the crackin chamber series.

26. In an apparatus of the class described, a series of stills, meansfor maintaining the stills of the series at successively highertemperatures, means for feeding oil into the first still of the seriesand for conveying oil from each of said stills to the next succeedingstill of the series, means for conveying vapors from each still, exceptthe first, and

discharging them intothe next preceding still of the series, and meansfor condens ng part of the vapors'so conveyed comprising means forbringing them in heat exchanging relation with condensate thereof formedin said next preceding still. a

27. A liquid refining apparatus comprising a series of liquid distillingchambers,

-means for maintaining the chambers at successively higher temperatures,means for feeding ,oil to the first chamber and from each chamber to thenext in the series, a condenser mounted in each chamber, said condenserbeing adapted to be cooled by the oil therein, means for conductingvapors from each chamber, except the first and discharging them into thecondenser mounted in the next preceding chamber and means for passingthe vapors remaining uncondensed in each condenser into the oil in thechamber in which said condenser is mounted.

V 28. A distilling apparatus comprising a series of narrow elongatedheated stills,

means for passing oil through eachv still, a a

distributor in each still for injecting vapor into the oil at aplurality of points along its passage therethrough, means for condensingand isolating as condensate a portion of the vapors evolved from theoil, in each still means for conducting the uncondensed portion of thevapors from each still, except the first, to the distributor of thenextpreceding still and means for conducting vapor to the distributor ofthe last still.

29. An apparatus for cracking petroleum oil constituents comprising agas heater adapted to heat a gas to a relatively high temperature, a.cracking reaction chamber separate from said heater and a combined heatexchanger and vaporizer, means for conducting oil to be treated intosaid vaporizer and for conducting a portion of the oil constituents fromsaid vaporizer into said reaction chamber, means for passing a heatcarrier gas into said heater to be heated therein to a high temperatureand for conducting the resulting heated gas into said reaction chamber,means for intimately contacting said heated gas with the oilconstituents in said reaction chamber to thereby heat and crack saidconstituents, means for conducting gas and vapor products from saidchamber into sa1dcomb1ned heat exchanger and vaporizer in heat exchangewith the oil introduced thereinto to thereby vaporize portions of theoil, a condenser for condensing readily condensible constituents fromthe said gas and vapor products, and means for conducting resultingseparated gas into said gas heater.

In testimony whereof I aifix my signature.

HENRY L. DOHERTY.

